Physics in Class 10 : Practice MCQ Questions & Answers with Explanations

Copper is non-magnetic and does not exhibit magnetic properties. Iron, nickel, and cobalt are ferromagnetic materials that are attracted to magnets and can be magnetized.

The right-hand thumb rule determines the direction of the magnetic field around a current-carrying conductor. Point the thumb in the direction of current; the curled fingers indicate the field direction.

Using Ohm's law $V = I \times R$, we get $V = 2 \times 5 = 10$ V.

In a series circuit, total resistance is the sum of individual resistances. $2\Omega + 3\Omega + 5\Omega = 10\Omega$.

Violet light has the shortest wavelength in the visible spectrum, followed by blue, green, and red.

Electric motors operate on the magnetic effect of electric current. When current flows through a conductor in a magnetic field, the resulting force causes motion.

The force on the conductor is given by $F = B \times I \times L$.

$F = 0.5 \times 3 \times 2 = 3$ N

According to Ohm's law ($I = V/R$), if resistance is doubled while voltage remains constant, the current is halved.

Using the lens formula and magnification formula with magnification = -1.5 and object distance = 30 cm, the focal length works out to -45 cm.

When a wire is cut into equal parts, the resistance of each part equals the total resistance divided by the number of parts. $\frac{10}{5} = 2$ ohms.

The power of a lens is given by $P = \frac{1}{f}$, where f is in metres.

For f = 20 cm = 0.20 m:

$P = \frac{1}{0.20} = +5$ D

Electric potential difference (voltage) is measured in volts (V). It represents the energy difference per unit charge between two points in a circuit.

The commutator in a DC motor reverses the direction of current in the armature windings, ensuring continuous rotation in one direction.

The pupil regulates the amount of light entering the eye by adjusting its size. It becomes smaller in bright light and larger in dim light for optimal vision.

An electromagnet produces a temporary magnetic field when electric current flows through it. The field can be switched on or off by controlling the current.

A concave mirror is used in car headlights to focus and direct light in a specific direction, enhancing visibility.

The retina detects light and converts it into electrical signals, which are sent to the brain for interpretation, allowing us to see.

The near point is the closest distance at which the eye can clearly focus. For a normal person, this is approximately 25 cm.

Electrical power is the rate at which energy is consumed or generated. It is calculated as Power = Current × Voltage, measured in watts.

Magnetic field strength is measured in tesla (T), named after Nikola Tesla. One tesla represents a field of 1 newton per ampere-metre.